1. Field of the Invention
The present invention relates to a radiation detection device having a radiation detector such as a flat panel detector contained in a cassette casing, and a radiation imaging apparatus including this radiation detection device, a consol device, and the like.
2. Description Related to the Prior Art
In a medical field, a radiation imaging apparatus for diagnostic imaging, e.g. an X-ray imaging apparatus that uses an X-ray as a radiation is widely known. The X-ray imaging apparatus is constituted of an X-ray generation device for applying an X-ray beam to a patient's body part to be examined, and an X-ray detection device for detecting the X-ray beam that has passed through the patient's body part. As the X-ray detection device, a cassette containing an imaging plate (IP) instead of an X-ray film, and a flat panel detector (FPD) are used in recent years. The IP has photostimulable storage phosphors for storing received radiation levels, and an X-ray image is produced by reading the IP with a specific laser scanner. The FPD, on the other hand, converts the received X-ray beam into signal charges, and produces the X-ray image in real time. Furthermore, a cassette-type FPD, in which the FPD is contained in a casing of the same shape and size as those of the cassette of the X-ray film or the IP, is recently developed so that the cassette-type FPD is loaded on the conventional X-ray imaging apparatus, instead of the X-ray film cassette.
The cassette-type FPD is frequently carried about because of being shared among a plurality of X-ray imaging apparatuses, or often moved with the portable X-ray imaging apparatus for use in radiography in a consulting room or a sick room. The frequent carriage increases the possibility of a break of the FPD by dropping or bumping the cassette-type FPD during the carriage.
To prevent use of the broken cassette-type FPD, for example, according to Japanese Patent Laid-Open Publication No. 2005-177379, the cassette-type FPD has a shock detection circuit and a self diagnostic circuit. In this cassette-type FPD, when the shock detection circuit detects a shock, the self diagnostic circuit is actuated to detect the presence of a failure. Also, in U.S. Pat. No. 7,514,703, the cassette-type FPD has an accelerometer. When the accelerometer detects an abnormal acceleration, electric power feeding to every part is stopped.
In the Japanese Patent Laid-Open Publication No. 2005-177379, the self diagnostic circuit diagnoses whether or not the cassette-type FPD is workable. However, even if the cassette-type FPD is workable, the image quality of the X-ray image is sometimes degraded to a level insufficient for a medical diagnosis. The self diagnosis cannot ensure the image quality of the X-ray image. In the U.S. Pat. No. 7,514,703, the cassette-type FPD stops feeding the electric power based on only the acceleration. Thus, whether or not the cassette-type FPD is broken, the FPD become unusable.
Furthermore, since the FPD is expensive, few medical institutions keep the extra cassette-type FPD on hand. Therefore, even if the cassette-type FPD is partly damaged, it is desirable to temporarily use the partly damaged cassette-type FPD as long as it can produce the X-ray image adequate for the medical diagnosis.